I only do all grain but that's cause I'm fancy. It takes hours more in your brew day and it takes a lot more work, learning, and equipment to do all grain. Still, I won't go back to extract and I'm still learning how to mash after 20 batches or so. Yep, fancy.

If you only look at the raw costs and if your time is worth more than minimum wage, it's a net loss to go AG. The ability to dial in recipes and to fully realize the craft of brewing is perhaps invaluable though. Also, many recipes aren't quite possible to hit exactly using extract.

For me it's about control.
Plenty of people make great beers with extract (DME or LME), but I like to be able to tailor my beers to my specific taste.
All grain is longer, and has more equipment involved, but if you are like many of us, and really like the "science" of brewing, then all grain is definitely the way to go.
Try some partial mash recipes to get a sense of the process, and most important, read,read,read.
I started all grain with BIAB(brew in a bag) and moved on to a mash tun,grain mill, growing hops,making keggles...ect.
If your really hooked, do it, you won't regret it for a second.

On a pound for pound basis, yes I think all grain is much cheaper than buying extracts. Remember, you're basically paying someone else to extract all the potential points from a grain and condense it for you with DME or LME. That being said, once you factor on the never ending purchases and upgrades I don't think that I'll ever be ahead really...

Its cheaper in the end. When you have a grain mill and can buy sacks of grains. But the problem is you pay a lot more upfront for all grain than you do you extract. Also it's pretty hard to screw up an extract batch but I've mashed a couple all grain way too high or way too low and didn't really get the beer I was looking for.

If you only look at the raw costs and if your time is worth more than minimum wage, it's a net loss to go AG. The ability to dial in recipes and to fully realize the craft of brewing is perhaps invaluable though. Also, many recipes aren't quite possible to hit exactly using extract.

My all-grain batches are cheaper per batch, slightly, than extract. But if I wanted I could cut the costs further. Buying malts in bulk brings substantial savings. Of course, buying hops in bulk and repitching yeast help too, but you can do those with extract.

And yeah, there's certain styles you can't really get perfect with extract. Certain styles requiring various adjuncts (Oatmeal Stout for example) that require mashing to get the full effect. You can get away with steeping them, but there's downsides. However, I'd say there's not a style out there that can't be brewed partial mash. Light lagers would be the hardest, but I'd think if you're really careful you could do it.

For me, it's have precise control over my base malt (I have yet to see, say, a Golden Promise extract, and while you can find Maris Otter or Munich extracts, I can't get them locally and would have to order them online if I wanted them), and more importantly control over fermentability that keep me doing all-grain.

I don't think it takes too much longer, at least if you brew AG with BIAB, plus by going to 10 gallons or more, you cut back the brew time per 5 gallon batch. It is nice to have control and formulate recipes. I still do extract sometimes but only when I need to whip up something for a party for people that don't care much.

What really got me to switch to all-grain was that most of the extract recipes in Brewing Classic Styles called for liquid extract and if I didn't use the whole can, I'd have to store it or plan out my recipes to go through my leftovers.